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Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – May 15, 2019

This content was originally published by the Longmont Observer and is licensed under a Creative Commons license.

In Brief:

Temperatures 15-20F above normal are the norm for a couple more days with high pressure stacked up through the atmosphere. Friday, a deep trough moves in kicking off storms and cooling us to below normal levels and returning a chance of rain for much of next week.

Forecast Discussion:

We have high pressure over the state today and weak winds (Figure 1). Overhead in the upper atmospheric map (Figure 2) the center of the ridge line is almost overhead. This will past to the east today changing the flow aloft from northwest flow to a southwest flow. That changes the drift direction of the afternoon storms that move off the mountains and warms us a bit more (Figure 3). There is a chance of afternoon thunder showers everyday around time of maximum heating (2-5pm).

The Longer Range Forecast:

Friday we see the change occur with a deep trough moving in from the west (red line digging towards us in Figure 4). We'll keep an eye on the amount of moisture that can make it in by Friday to see IF we may see severe weather nearby (Figure 3). From Saturday on into next week we hover in the 60'sF for highs with many chances for rain again. More later!

Figure 1: The forecast surface map for Wednesday PM from NCEP.
Figure 2: NCEP 500 mb upper air map from Tuesday PM. Blue lines are ridges, red lines are troughs.
Figure 3: the graphical forecast for the next 10 days for Longmont, CO from weatherunderground.com
Figure 4: The 500mb forecast upper air analysis for Wednesday morning. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.

Current Weather

Sunny

Sunny

49°F

UV Index
3 Moderate
Pressure
29.74 Steady
Visibility
8 miles
Dewpoint
17 °F
Humidity
28%
Wind
W 4.3 mph
Gust
11.1 mph
Wind Chill
48 °F

Hourly Forecast

Today
10 AM
53°F
Intermittent clouds
Today
11 AM
56°F
Intermittent clouds
Today
12 PM
57°F
Intermittent clouds
Today
1 PM
59°F
Intermittent clouds
Today
2 PM
59°F
Intermittent clouds
Today
3 PM
60°F
Intermittent clouds
Today
4 PM
59°F
Intermittent clouds
Today
5 PM
59°F
Intermittent clouds
Today
6 PM
57°F
Intermittent clouds
Today
7 PM
56°F
Intermittent clouds
Today
8 PM
53°F
Intermittent clouds
Today
9 PM
50°F
Intermittent clouds

7 Day Forecast

Intermittent clouds

Wednesday

60 °F

Breezy this morning; otherwise, cool with times of clouds and sun


Mostly cloudy

Wednesday Night

40 °F

Increasing clouds


Partly sunny w/ showers

Thursday

53 °F

Times of clouds and sun with a couple of showers; cool


Partly cloudy

Thursday Night

41 °F

Partly cloudy


Mostly cloudy

Friday

57 °F

Mostly cloudy


Partly cloudy

Friday Night

39 °F

Partly cloudy


Mostly sunny

Saturday

66 °F

Mostly sunny and warmer


Mostly cloudy w/ t-storms

Saturday Night

43 °F

Mostly cloudy with showers and thunderstorms late


Mostly cloudy

Sunday

64 °F

Mostly cloudy with a thunderstorm in spots in the afternoon


Intermittent clouds

Sunday Night

44 °F

A thunderstorm in the evening; otherwise, becoming clear


Sunrise and Sunset

Sunrise
5:51 AM
Sunset
8:03 PM

Based on AccuWeather data